Patent application title: MODULAR STRAND GUIDE ROLLER

Abstract:

The invention is based on the object of creating a strand guide roller
being configured in a modular manner, which can be retrofitted to
different stand casting widths without any substantial effort, and which
has a cooling effect starting from the core regions of the roller
extending up to the region near the surface thereof, thereby improving
the life of the strand guide roller and achieving a comparatively
cost-effective maintenance. The problem is solved according to the
invention in that a first centrally disposed, axially extending flow
channel (11 and a second centrally disposed, axially extending flow
channel (12) are present in each roller module (2, 3, 4), that flow
channels (15, 16) are disposed in the region near the surface of each
roller module (2, 3, 4), and that connecting channels (17) connect the
respective flow channels (15) to the first separate flow channel (11),
and that connecting channels (18) connect the respective flow channels
(16) to the separate second flow channel (12).

Claims:

1-13. (canceled)

14. A modular strand guide roller for a strand guide unit of a continuous
casting plant, wherein the strand guide roller comprises: at least a
first and a second roller module, which are disposed side by side in an
axial direction, wherein the first roller module has a centrally located
roller journal at an end face that faces the second roller module; a
middle bearing, which is positioned between the first and second roller
modules for mounting and supporting the roller journal of the first
roller module; a plug connection formed between the second roller module
and the roller journal for plug connection of the first and second roller
modules with each other; and a central flow channel that runs axially in
the roller modules for conveying a coolant, wherein the centrally located
and axially running flow channel consists of a first separate flow
channel and a second separate flow channel; wherein flow channels are
formed in the region near the surface of an outer periphery of each
roller module that guides and supports the metal strand; wherein first
connecting channels connect respective flow channels with the first
separate flow channel, and second connecting channels connect further
respective flow channels with the second separate flow channel; and
wherein the flow channels are arranged in pairs.

15. The strand guide roller in accordance with claim 14, wherein a
chamber is formed at least at one end of each pair of flow channels to
deflect the coolant.

16. The strand guide roller in accordance with claim 15, wherein the flow
channels and the chambers are tightly sealed from outside with detachable
individual or common annular covers.

17. The strand guide roller in accordance with claim 14, wherein the
respective flow channels of the paired flow channels are connected by the
first connecting channels with the respective first flow channel, and the
further respective flow channels of the paired flow channels are
connected by the second connecting channels with the respective second
flow channel.

18. The strand guide roller in accordance with claim 17, wherein the
first connecting channel connects a supply-side outlet of the first flow
channel with a discharge-side inlet of the respective flow channel of the
paired flow channels.

19. The strand guide roller in accordance with claim 17, wherein the
second connecting channel connects a supply-side outlet of the further
respective flow channel of the paired flow channels with a discharge-side
inlet of the second flow channel.

20. The strand guide roller in accordance with claim 14, wherein the
first flow channel of the first roller module is connectable to a coolant
inlet, and the second flow channel of a respective roller module is
connectable to a coolant outlet.

21. The strand guide roller in accordance with claim 14, and further
comprising a coupling sleeve provided to connect the second flow channel
of the first roller module with the first flow channel of the second
roller module.

22. The strand guide roller in accordance with claim 1, wherein a
direction of flow of the coolant is reversible.

23. The strand guide roller in accordance with claim 14, wherein the
first and second separate flow channels are each formed as sections of a
common central flow channel and are separated from each other only by a
barrier.

24. The strand guide roller in accordance with claim 14, wherein the flow
channels are formed axially parallel, helically, or as an annular gap in
a region of the roller module that is near the surface.

25. A strand guide unit for a metal strand emerging from a mold of a
continuous casting plant, wherein the strand guide unit has at least one
strand guide roller that consists of a first roller module and a second
roller module designed in accordance with the features of claim 14.

26. A method for operating a strand guide unit in accordance with claim
25, wherein the coolant flows in opposite directions in adjacent strand
guide rollers, adjacent roller segments, or in an upper and lower frame
of a segment.

Description:

[0001] The invention concerns a modularly constructed strand guide roller
for the strand guide unit of a continuous casting plant in accordance
with the features of the preamble of claim 1, a strand guide roller in
accordance with the features of claim 13, and a method for operating it
in accordance with claim 14.

[0002] A strand guide roller is known from EP 1 485 218 B1, which,
however, proceeding from the objective of the invention, focuses on a
rotary leadthrough for a cooling water inlet and outlet of a support
and/or transport roller pivoted at least at the end with journals in
bearing blocks, especially in a continuous casting plant. The outer
region of the water-cooled support and/or transport roller has axial
channels and channels that run into or out of these axial channels and to
a central distribution system. The central distribution system consists
of a central bore in the support and/or transport roller and of a tubular
line arranged therein, which has a central supply channel for the cooling
water and with the central bore forms an annular channel for the removal
of the cooling water.

[0003] The strand guide roller disclosed in the cited document consists of
two or more roller segments, each of which is supported at its end. This
type of end bearing of the individual roller segments is expensive and
entails considerable labor for the assembly and disassembly of the
bearing units during maintenance of the strand guide unit.

[0004] Furthermore, as a result of this type of end bearing of the roller
segments, strand guide units cannot be changed over to other casting
machine widths without considerable labor.

[0005] WO 2007/121821 A1 discloses a strand guide roller of a strand guide
unit that consists of at least two roller sections, on which a strand
cast by a continuous casting machine is guided, according to which a plug
connection is formed between the two roller segments, and only one
bearing is provided, which is designed as an undivided single bearing.
Aside from a number of advantages over the cited document, the sole
cooling medium flow channel, which runs centrally over essentially the
whole width of the strand guide roller, fails to develop a sufficient
cooling effect for the strand guide roller. Especially the region of the
strand guide roller near the surface does not experience sufficient
cooling to reduce the wear of the strand guide roller that results from
chemical and mechanical stress. Therefore, the centrally running flow
channel serves primarily to cool the inner rings of the bearing in the
area of the journal of the strand guide roller or the roller segments.

[0006] The internally cooled strand guide roller additionally disclosed by
the documents WO 2004/094087 A1 and EP 1 646 463 B1 comprises a central
rotatable shaft and several roller shells that have integrated coolant
channels and are secured against rotation and supported on the shaft.
Practical experience shows that these strand guide rollers with roller
shells slipped onto them not only show unsatisfactory cooling of the
roller barrels but also an enormously high proportion of sealing elements
and thus do not represent a maintenance-friendly and operationally
reliable solution.

[0007] Therefore, the objective of the invention is to create a modularly
constructed strand guide roller which can be changed over to different
continuous casting widths without any great effort and which has a
cooling effect that extends from the core region to the region near the
surface and thus improves the service life of the strand guide roller.

[0008] A further objective of the invention is to create a modularly
constructed strand guide roller that allows comparatively low-cost
maintenance. Yet another objective of the invention is to create a strand
guide unit with strand guide rollers that are improved with respect to
increased service life and easier maintenance.

[0009] In accordance with the invention, the objective is achieved by the
features of claim 1 and the features of claims 13 and 14. According to
the features of claim 1, the modularly constructed strand guide roller
for the strand guide unit of a continuous casting plant comprises
[0010] at least a first roller module and a second roller module, where
the two roller modules are disposed side by side in the axial direction,
and the first roller module has a centrally located roller journal at its
end face that faces the second roller module, [0011] a middle bearing,
which is arranged between the first and second roller modules for
mounting and supporting the roller journal of the first roller module,
where the middle bearing is an undivided single bearing, [0012] a plug
connection formed between the second roller module and the roller journal
for plug connection of the first and second roller modules with each
other, and [0013] a flow channel that runs centrally in the roller
modules for conveying a coolant, such that, in accordance with the
invention, the centrally running flow channel consists of a first
separate flow channel and a second separate flow channel, and such that
[0014] the first and second separate flow channels of each roller module
are connected by connecting channels with flow channels formed in the
region near the surface.

[0015] In a further refinement of the invention, the flow channels formed
in the region near the surface of each roller module are present in
pairs. In this regard, in a first flow channel of the paired flow
channels, the coolant flows in the opposite direction from the coolant
that flows in the centrally running flow channels, and in a second flow
channel of the paired flow channels, the coolant flows in the same
direction as the coolant that flows in the centrally running flow
channels. An open coolant circulation is thus formed in each roller
module. At one end of the paired flow channels, a chamber is formed,
which serves to deflect the coolant within the first roller module and
the following roller module. The chambers are tightly sealed from the
outside with a cover, so that no coolant can escape.

[0016] In addition, the first flow channel of each pair of flow channels
is connected by a corresponding first connecting channel with the first
centrally running flow channel, and the second flow channel of each pair
of flow channels is connected by a corresponding second connecting
channel with the second centrally running flow channel.

[0017] In this regard, the connection is produced, for one thing, in such
a way that the first connecting channel connects the supply-side outlet
of the first centrally running flow channel with the discharge-side inlet
of the respective flow channel of the paired flow channels, and, for
another, in such a way that the second connecting channel connects the
supply-side outlet of the second respective flow channel of the paired
flow channels with the discharge-side inlet of the second centrally
running flow channel.

[0018] As a result of this type of course of the flow channels within the
roller module in accordance with the invention, not only are the core
region and the region of the bearing cooled, as is already known from the
prior art, but also the region near its surface.

[0019] In a further refinement of the invention, when the plug connection
between the first and second roller modules has been effected, the second
centrally running flow channel of the first roller module and the first
centrally running flow channel of the second roller module are connected
by a coupling sleeve, so that the coolant can flow from the second
centrally running flow channel of the first roller module into the first
centrally running flow channel of the second roller module.

[0020] The second roller module and each additional roller module of the
strand guide roller is, where the totality of the construction of the
flow channels and connecting channels is concerned, constructed
identically to the first roller module. For example, in the case of a
strand guide roller with a first and a second roller module, a first open
coolant circulation is joined with a second open coolant circulation to
form a common open coolant circulation, such that the first coolant
circulation can be connected to a coolant inlet, and the second coolant
circulation can be connected to a coolant outlet.

[0021] Advantageously, the modularly constructed strand guide roller makes
it possible for the first time to construct a strand guide roller for
different continuous casting widths, which is adequately cooled both in
the core region and in the region near the surface.

[0022] Due to the small axial extent of the bearing gaps between the
individual roller modules, the advantageous result is obtained that only
greatly reduced or minimized bulging of the slab occurs in the regions
not supported by the strand guide rollers.

[0023] The design of the flow channels in accordance with the invention
allows overall improved cooling of the strand guide roller with the
result that the service life of the roller is increased and that the
spectrum of steel grades that can be cast is expanded.

[0024] The provision of detachable covers for the peripheral flow channels
or the chambers has the advantage that these would now be accessible and
could be cleaned.

[0025] With a helical arrangement of the peripheral flow channels, they
can be arranged and operated in groups, e.g., as a multiple thread. A
first group could then be used for the forward movement of the coolant
and a second group for its return movement.

[0026] A variable or alternating flow direction of the coolant in adjacent
strand guide rollers, adjacent roller segments, or in upper and lower
frames of a segment helps to even out the cooling effect on the strand or
slab.

[0027] Further advantages and features of the present invention are
apparent from the dependent claims and the description of a specific
embodiment illustrated in the accompanying drawings.

[0028] FIG. 1 is a cross-sectional drawing, along sectional line A-A in
FIG. 4, of a strand guide roller that consists of three roller modules.

[0029]FIG. 2 shows detail "Z" in FIG. 1 with an enlarged view of the flow
channels and connecting channels that convey the stream of coolant from
the core region to the region near the surface.

[0030] FIG. 3 is a cross section of the strand guide roller in an enlarged
view along line D-D in FIG. 1.

[0031] FIG. 4 is a cross section of the strand guide roller in an enlarged
view along line B-B in FIG. 1.

[0032]FIG. 5 is a view of the second or middle roller module in direction
"A" in FIG. 6.

[0033] FIG. 6 shows the second or middle roller module of the strand guide
roller in the longitudinal section along line C-C in FIG. 5.

[0034] FIG. 7 is a side view of the second or middle roller module of the
strand guide roller according to FIG. 6.

[0035] The strand guide roller 1 shown in FIG. 1 consists of a first
roller module 2, a second roller module 3, and a third roller module 4.
All of the roller modules are assembled into a strand guide roller
according to the prior-art document WO 2007/121821, specifically, by a
first plug connection between the second or middle roller module 3 and
the inner roller journal 2.1 of the first roller module 2 and by a second
plug connection between the third roller module 4 and the inner roller
journal 3.1 of the second or middle roller module 3.

[0036] The inner roller journal 2.1 of the first roller module 2 is
mounted in an undivided middle bearing 5, and the inner roller journal
3.1 of the second or middle roller module 3 is mounted in an undivided
middle bearing 6. Both of the middle bearings 5, 6 are advantageously
designed relatively short in their axial extent, which means that the
transition region 7 between the roller modules 2, 3 and 3, 4 are likewise
designed relatively short, so that advantageously a bulging of the cast
metal strand (slab) is minimized or greatly reduced.

[0037] The outer roller journal 2.2 of the roller module 2 and the outer
roller journal 4.1 of the roller module 4 of the strand guide roller 1
are each mounted in an outer bearing 8 and 9, respectively.

[0038] The second or middle roller module 3 is not mounted in the middle
bearing 5, and the third roller module 4 is not mounted in the middle
bearing 6. A plug connection, for example, is provided as the means of
connection between the respective roller modules 2, 3 and 3, 4. In this
regard, as is seen best in FIG. 6, the roller modules 3 and 4 have a
recess 10 on their end face that faces the first roller module 2 and the
second roller module 3, respectively. A component 23, for example, one
with an annular design, is inserted into this recess in such a way that
it is secured against rotation. An extension 2.1.1 or 3.1.1 of the
respective roller journal is machine-faced relative to the roller journal
itself and can be connected in a positive-locking way with the component
23. Further details of the positive-locking connection or plug connection
will not be discussed here, since these are not objects of the present
invention.

[0039] As FIG. 1 also shows, each roller module 2, 3, 4 has a first and
second centrally running flow channel 11 and 12, respectively. In this
regard, the flow channel 11 of the roller module 2 can be connected to a
coolant inlet 13, and the flow channel 12 of the roller module 4 can be
connected to a coolant outlet 14.

[0040] To allow complete cooling of each roller module of the strand guide
roller 1, i.e., not only cooling of the core region and bearing region
but also cooling of the region near the surface, each of the roller
modules has additional flow channels and connecting channels, which,
together with the centrally running flow channels 11, 12, form an open
coolant circulation in each roller module 2, 3, 4 and, ultimately, in
each strand guide roller 1 designed in accordance with the invention.

[0041] To this end, as shown in FIG. 2, axially running flow channels 15,
16 are formed in the region near the surface of the outer periphery of
each roller module 2, 3, 4 that guides and supports the metal strand.
First connecting channels 17 and second connecting channels 18 connect
the axially running flow channels 15, 16 with the centrally running flow
channels 11, 12 to form an open coolant circulation.

[0042] In this regard, the coolant circulation is formed in such a way
that, as FIG. 3 shows, the flow channels 15, 16 are arranged in pairs in
the region near the surface, and, specifically, are preferably regularly
distributed around the periphery, where one of the flow channels of the
paired flow channels 15, 16 is connected by the connecting channel 17
with the supply-side outlet 11.1 of the flow channel 11, and the other
flow channel of the paired flow channels 15, 16 is connected by the
connecting channel 18 with the discharge-side inlet 12.1 of the flow
channel 12.

[0043] As is best seen in FIG. 2, the paired flowed channels 15, 16 are
each sealed at the end, individually or together, by covers 19 and 27 in
such a way that these ensure a change in the direction of flow of the
coolant in conjunction with corresponding chambers 20 formed at the end
face in the given roller module.

[0044] A special advantage of a coolant circulation of this type is that
the connecting channels 17, 18 are placed in each roller module 2, 3, 4
at the journal end in the direction of the coolant inlet 13, and thus the
peripheral surface of each roller module is free of any machining process
for forming connecting channels with necessarily present sealing
elements. In the mounted state of the strand guide roller 1, each second
centrally running flow channel 12 of the roller modules 2 and 3 is
connected by a coupling sleeve 21 with the respective first centrally
running flow channel 11 of the roller module 3 and 4. As a result, the
open coolant circulation of each roller module is brought together to
form an open coolant circulation of the strand guide roller 1.

[0045] To provide better understanding of the coolant circulation within
the strand guide roller 1, the direction of flow of the coolant 22 from
the coolant inlet 13 to the coolant outlet 14 is indicated by directional
arrows.

[0046] The coolant 22 flowing into the flow channel 11 of the roller
module 2 flows at the end of the flow channel 11 into the connecting
channel 17 and enters flow channel 15 of the paired flow channels 15, 16.
At the end of flow channel 15, the coolant 22 is carried into flow
channel 16 of the paired flow channels 15, 16 and enters the
discharge-side inlet 12.1 of the second centrally running flow channel
12, from which it is carried into the first centrally running flow
channel 11 of the roller module 3 via the coupling sleeve 21.

[0047] The further course of the flow of the coolant 22 in the roller
modules 3 and 4 occurs analogously to the course of the flow described
for roller module 2, so that there is no need to provide further details
here.

[0048]FIG. 2 is an enlarged detail view of section "Z" in FIG. 1 and
shows the relevant design of the flow channels and connecting channels of
roller module 2 and the direction of flow of the coolant 2. The same
parts in FIGS. 1 and 2 are identified by the same reference numbers.

[0049] FIG. 3 is a cross-sectional view along line D-D in FIG. 1. It shows
the region of the plug connection between roller module 2 and roller
module 3 as well as the axially running flow channels 15 and 16, which
are arranged in pairs in the region of roller module 3 near the surface,
with the cover 27 removed. Each pair of flow channels 15, 16 comprises a
flow channel 15 with coolant 22 flowing in and a flow channel 16 with
coolant 22 flowing out. The flow channels in a paired set of flow
channels 15, 16 are connected with each other by a chamber 20 placed in
the roller module. In addition, the drawing shows the second centrally
running flow channel 12 in the roller journal 2.1 of the roller module 2.

[0050] FIG. 4 is a cross-sectional view of roller module 3 along line B-B
in FIG. 1 with the paired flow channels 15 and 16 arranged near the
surface and with the centrally arranged, first flow channel 11.

[0051]FIG. 5 is a side view of roller module 3 shown in FIG. 6. The
axially running flow channels 15, 16, which are arranged in pairs in the
region of the roller module 3 that is near the surface, are tightly
sealed at the end with a preferably detachable individual or common cover
27. The drawing also shows the centrally running flow channel 11, 12 of
the roller module 3.

[0052] The flow channel 11 is connected with the respective flow channels
15 of the paired flow channels 15, 16 by the connecting channels 17,
which run at an acute angle, while the flow channel 12 is connected with
the respective flow channels 16 of the paired flow channels 15, 16 by the
connecting channels 18, which run at an acute angle.

[0053] FIG. 6 shows a longitudinal section along line C-C in FIG. 5. The
roller module 3 and roller journal 3.1 are shown once again in a clearly
understandable way. Also shown is the preferably polygonally designed
extension 3.1.1 of the roller journal 3.1.

[0054] In addition to the arrangement of the flow channels and connecting
channels that has already been described in detail above, the roller
module 3 has a recess 10, which is located on the end face that faces
away from the roller journal 3.1. The recess 10 holds an annular
component 23, which is secured against rotation by suitable securing
means 24, for example, dowel pins. In this regard, the inside of the
annular component 23 has a cross section that corresponds to the
cross-sectional shape of the extension 2.1.1 of the roller journal 2.1,
for example, a polygonal shape. On the inlet side of the central flow
channel 11, the recess 10 is followed by a mounting bore 25 for the
coupling sleeve 21 (see also FIG. 1). In this regard, the diameter of the
mounting bore 25 is greater than the diameter of the centrally running
flow channel 11. In addition, the extension 3.1.1 of the roller journal
3.1. of the roller module 3 has a mounting bore 26 that serves the same
purpose.

[0055] FIG. 7 is another side view of the roller module 3 shown in FIG. 6.
As in the design according to FIG. 5, in the region near the surface, the
paired flow channels 15, 16 are arranged around the flow channel 11 or 12
and are sealed by covers 19. A chamber 20, which is shown only in FIG. 6,
joins the paired flow channels 15, 16, so that the flow of the coolant 22
is deflected in it.

[0056] The side view also shows the polygonal design of the extension
3.1.1 as well as the mounting bore 26 for the coupling sleeve 21 and the
centrally running flow channel 12, 11.